The present invention relates to circuit breakers, and more particularly to blocking apparatuses for circuit breaker contact structures.
Automatic circuit breakers of relatively high current carrying capacity utilize a movable contact arm assembly to carry the current. The movable contact arm assembly is generally separate from a complementary stationary contact by electromagnetic forces that overcome the holding force of contact springs (i.e., blow open forces), or, by other short-circuit conditions that signals an actuator to cause an operating mechanism to separate the contact via powerful mechanism operating springs and various links.
After the movable contact arm assembly is separated from the stationary contact, and the short-circuit condition is cleared, the electrical contact between the stationary and movable contacts must be closed and the operating mechanism reset. If the contact arm assembly separates via blow open forces, the operating mechanism remains in the xe2x80x9cONxe2x80x9d position, unless the short-circuit condition also causes the actuator to trigger the operating mechanism, whereby the operating mechanism is in the xe2x80x9cTRIPPEDxe2x80x9d position. Also, if the contact arm assembly separates via the operating mechanism, the operating mechanism is in the xe2x80x9cTRIPPEDxe2x80x9d position.
In any of the above situations where the contact arm assembly is separated, no current flows through the circuit breaker. A handle integral with the operating mechanism must be moved beyond the xe2x80x9cOFFxe2x80x9d position prior to being returned to the xe2x80x9cONxe2x80x9d position and having the contact arm assembly in electrical contact with the stationary contacts.
Is often desirable to close the movable contact assembly very rapidly. With conventional operating mechanism configurations, this requires a high speed and high torque force applied to the handle of the operating mechanism to reposition the operating mechanism springs. This high speed and high torque force may be provided manually, or maybe provided by a motorized charging mechanism. The speed of contact closure depends on the speed that the high torque force is applied, i.e., by a motorized charging mechanism.
An apparatus is provided that blocks a movable contact from being in electrical contact with a stationary contact in a circuit breaker contact structure. The circuit breaker contact structure interacts with an operating mechanism. The operating mechanism provides a closing force to move the movable contact into connection with the stationary contact. The apparatus includes a link connected to the movable contact, the link moving between a first position and a second position. The first position of the link holds the movable contact away from stationary contact against the closing force of the operating mechanism. The second position of the link releases the movable contact so that the closing force of the operating mechanism moves the movable contact into connection with the stationary contact.